BZOJ4353 Play with tree[树剖]

复习几乎考不到的树剖。维护min以及min个数，打set和add标记即可，注意set优先级优于add。

 #include<iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<cmath>
 #define dbg(x) cerr << #x << " = " << x <<endl
 using namespace std;
 typedef long long ll;
 typedef double db;
 typedef pair<int,int> pii;
 template<typename T>inline T _min(T A,T B){return A<B?A:B;}
 template<typename T>inline T _max(T A,T B){return A>B?A:B;}
 template<typename T>inline char MIN(T&A,T B){return A>B?(A=B,):;}
 template<typename T>inline char MAX(T&A,T B){return A<B?(A=B,):;}
 template<typename T>inline void _swap(T&A,T&B){A^=B^=A^=B;}
 template<typename T>inline T read(T&x){
     x=;int f=;char c;while(!isdigit(c=getchar()))if(c=='-')f=;
     while(isdigit(c))x=x*+(c&),c=getchar();return f?x=-x:x;
 }
 const int N=1e5+,INF=0x7f7f7f7f;
 struct thxorz{int to,nxt;}G[N<<];
 int Head[N],tot;
 int n,q;
 inline void Addedge(int x,int y){
     G[++tot].to=y,G[tot].nxt=Head[x],Head[x]=tot;
     G[++tot].to=x,G[tot].nxt=Head[y],Head[y]=tot;
 }
 #define y G[j].to
 int fa[N],son[N],topfa[N],st[N],dep[N],cnt,sonc[N];
 void dfs1(int x,int f){
     int tmp=-;sonc[x]=;fa[x]=f,dep[x]=dep[f]+;
     for(register int j=Head[x];j;j=G[j].nxt)if(y^f)dfs1(y,x),sonc[x]+=sonc[y],MAX(tmp,sonc[y])&&(son[x]=y);
 }
 void dfs2(int x,int topf){
     topfa[x]=topf,st[x]=cnt++;if(!son[x])return;dfs2(son[x],topf);//order the point in dfs2,not in dfs1.
     for(register int j=Head[x];j;j=G[j].nxt)if((y^fa[x])&&(y^son[x]))dfs2(y,y);
 }
 #undef y
 #define lc i<<1
 #define rc i<<1|1
 #define all 1,1,n-1
 int minv[N<<],mint[N<<],stag[N<<],atag[N<<];
 inline void Pushup(int i){
     if(minv[lc]<minv[rc])mint[i]=mint[lc];
     else mint[i]=minv[lc]>minv[rc]?mint[rc]:mint[lc]+mint[rc];
     minv[i]=_min(minv[lc],minv[rc]);
 }
 inline void Pushdown(int i,int L,int R){
     if(~stag[i]){
         minv[lc]=minv[rc]=stag[i]+atag[i];
         atag[lc]=atag[rc]=atag[i],stag[lc]=stag[rc]=stag[i];
         mint[lc]=(L+R>>)-L+,mint[rc]=R-(L+R>>);
         stag[i]=-,atag[i]=;
     }
     else{
         minv[lc]+=atag[i],minv[rc]+=atag[i];
         atag[lc]+=atag[i],atag[rc]+=atag[i];
         atag[i]=;
     }
 }
 void Build(int i,int L,int R){
     if(L==R){mint[i]=,stag[i]=-;return;}
     int mid=L+R>>;Build(lc,L,mid),Build(rc,mid+,R),Pushup(i),stag[i]=-;
 }
 void Update_set(int i,int L,int R,int ql,int qr,int c){
     if(ql<=L&&qr>=R){minv[i]=c,mint[i]=R-L+,stag[i]=c,atag[i]=;return;}
     int mid=L+R>>;Pushdown(i,L,R);
     if(ql<=mid)Update_set(lc,L,mid,ql,qr,c);
     if(qr>mid)Update_set(rc,mid+,R,ql,qr,c);
     Pushup(i);
 }
 void Update_add(int i,int L,int R,int ql,int qr,int c){
     if(ql<=L&&qr>=R){minv[i]+=c,atag[i]+=c;return;}
     int mid=L+R>>;Pushdown(i,L,R);
     if(ql<=mid)Update_add(lc,L,mid,ql,qr,c);
     if(qr>mid)Update_add(rc,mid+,R,ql,qr,c);
     Pushup(i);
 }
 int Query_min(int i,int L,int R,int ql,int qr){//dbg(i),dbg(ql),dbg(qr),dbg(minv[i]);
     if(ql<=L&&qr>=R)return minv[i];
     int mid=L+R>>,ret=INF;Pushdown(i,L,R);
     if(ql<=mid)MIN(ret,Query_min(lc,L,mid,ql,qr));
     if(qr>mid)MIN(ret,Query_min(rc,mid+,R,ql,qr));
     return ret;
 }
 inline void Tree_set(int x,int y,int c){
     while(topfa[x]^topfa[y]){
         if(dep[topfa[x]]<dep[topfa[y]])swap(x,y);//dbg(x);dbg(y);
         Update_set(all,st[topfa[x]],st[x],c);x=fa[topfa[x]];
     }
     if(dep[x]>dep[y])swap(x,y);
     if(x^y)Update_set(all,st[x]+,st[y],c);
 }
 inline int Tree_min(int x,int y){
     int ret=INF;
     while(topfa[x]^topfa[y]){
         if(dep[topfa[x]]<dep[topfa[y]])swap(x,y);//dbg(x),dbg(st[topfa[x]]),dbg(st[x]);
         MIN(ret,Query_min(all,st[topfa[x]],st[x]));x=fa[topfa[x]];
     }
     if(dep[x]>dep[y])swap(x,y);
     if(x^y)MIN(ret,Query_min(all,st[x]+,st[y]));
     return ret;
 }
 inline void Tree_add(int x,int y,int c){
     int minx=Tree_min(x,y);//dbg(minx);
     if(minx+c<)c=-minx;
     while(topfa[x]^topfa[y]){
         if(dep[topfa[x]]<dep[topfa[y]])swap(x,y);
         Update_add(all,st[topfa[x]],st[x],c);x=fa[topfa[x]];
     }
     if(dep[x]>dep[y])swap(x,y);
     if(x^y)Update_add(all,st[x]+,st[y],c);
 }
 int main(){//freopen("3.in","r",stdin);freopen("test.ans","w",stdout);
     read(n);read(q);
     for(register int i=,x,y;i<n;++i)read(x),read(y),Addedge(x,y);
     dfs1(,);dfs2(,);Build(all);//for(register int i=1;i<=n;++i)cout<<i<<" ",dbg(st[i]);
     for(register int i=,opt,x,y,c;i<=q;++i){
         read(opt),read(x),read(y),read(c);
         if(opt==)Tree_set(x,y,c);
         else Tree_add(x,y,c);
         printf("%d\n",!minv[]?mint[]:);
     }
     return ;
 }